Wrinkled Nanoporous Gold Films with Ultrahigh Surface-Enhanced Raman Scattering Enhancement

WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
ACS Nano (Impact Factor: 12.88). 06/2011; 5(6):4407-13. DOI: 10.1021/nn201443p
Source: PubMed

ABSTRACT Amplified by plasomonic nanostructured metals, Raman intensity of organic molecules and biomolecules can be dramatically improved, particularly at "hot spots" where intense electromagnetic fields are produced in the vicinity of narrow nanogaps between metallic nanostructures. Therefore, developing new substrates with a high density of "hot spots" has been the recent topic of intense study. Here we report wrinkled nanoporous gold films that contain abundant Raman-active nanogaps produced by deformation and fracture of nanowire-like gold ligaments. This novel nanostructure yields ultrahigh surface enhanced Raman scattering for molecule detection.

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    • "However, their in-plane structural features and smooth ligament surfaces resulted from chemical etching constrain the local electromagnetic field strength below the limit for SERS-based single molecule detection212223. The SERS performances of nanoporous metal films can be further improved by introducing 3D quasi-periodic wrinkles through thermal contraction of pre-strained polymer substrates (Fig. 1a)242526. Using this procedure detailed in the Method section, rich SERS-active nanostructures at the ridges of the wrinkles, such as nanogaps and nanotips, are produced by deformation and failure of metal ligaments during film shrinking. "
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